1. Field of the Invention:
The present invention relates to optical sorting machines for agricultural products.
2. Description of the Prior Art:
U.S. Pat. No. 4,454,029, of which applicant is the inventor, related to a bichromatic sorter for agricultural products. These sorters were based upon a pattern checking technique wherein portions of the descending agricultural product, such as coffee beans or peanuts, were inspected for unsatisfactory coloration. The unsatisfactory coloration that was detected was in the form of light or dark spots on the product, indicating a bad product. Upon sensing these undesirable spots, the sorter then rejected the undesirable product by causing it to fall into a different location from the desirable product. This technique of pattern checking allowed spots and other light or dark imperfections to be detected, but did not solve the problem of product having uniformly undesirable coloration, indicating, for example, overripeness or immaturity of the product. Further, while pattern sorting permitted color sorting, it was done at reduced accuracy when compared to ratiometric sorting.
Prior art sorters have been constructed as single units which are then assembled into groups of multiple independent units to allow higher volume operation. This technique of multiple independent units increased the space requirements according to the number of sorting units required, since in effect a chosen number of sorting units were arranged in parallel as if they were individual units. Further, it unduly increased the amount of electronic circuitry, because the scanning and control functions were repeated in each sorting unit. The unnecessarily large space requirements and increased electronics for multiple channel sorting did not afford any significant cost saving or efficiency for added sorting channels, since each added channel in effect added the cost of another sorting machine for that channel.